[Patent Document 1] JP-A-2008-176648
Patent document 1 recites a system which reports existence of an obstacle at an intersection to a driver of a vehicle. In Patent document 1, a road management apparatus detects a pedestrian located in a crosswalk or in an area adjacent to the crosswalk (also referred to as a crosswalk-adjacent area), and notifies a vehicle turning right or left of pedestrian detection information by a pedestrian-use traffic signal flashing an LED. An in-vehicle apparatus in the vehicle reports the pedestrian detection information to the driver of the vehicle using sounds or images. Thereby, the driver can acquire or recognize the detection information of the pedestrian located in the crosswalk or near the crosswalk.
It is noted that in the technology in Patent document 1, the driver may be notified of an existence of an obstacle whose necessity is not so high; thus, the driver may sense troublesome.